The goals of Biostatistics and Data Coordinating Core (BDCC) are to provide the biostatistical study design and analysis support, biomathematical modeling expertise and data analytic services to enhance the scientific quality of all projects. The BDCC will also provide the data management and research computing expertise necessary to design and implement data entry, data quality assurance and reporting via a secure World Wide Web (WWW)-based data management system (DMS) for the Randomized Clinical Trial (RCT) in Project 1. This DMS will support subject enrollment, eligibility confirmation, randomization and data collection at the clinical centers and tracking of subjects, data, and specimens at the BDCC. The BDCC will execute procedures for data security and access, data quality control, storage and back-up, and will provide periodic reports of accrual and follow-up. Core members will be involved in biostatistical and data coordination activities for all projects. The aims of the BDCC are to: 1. Biostatistics a) advice investigators in study design issues, including sample size and power considerations b) conduct statistical analyses of data from laboratory projects and clinical investigations to address specific research hypotheses defined in the project-specific proposals; c) assist with preparation for and writing of final reports, abstracts, manuscripts, and future research proposals; d) conduct exploratory analyses that may lead to generation of new hypotheses. 2. Data Coordination a) provide the analysis, design, development and implementation of a distributed Data Management System (DMS) supporting the RCT (Project 1) and relevant data from Project 2; b) providing training and assistance for research staff in the conduct of the RCT and in the use of the DMS; c) conduct all phases of protocol quality assurance, validation, query resolution and reporting for Project 1; d) design, develop and implement the analytical database for the trial data from Project 1, MRI data in Project 2, the genetics data from Project 3 and the pharmacology data in Project 4; e) create valid datasets of high scientific quality, combining the data from study specific sources and from the BDCC, for biostatistical analyses.